Email Subject Line Counter
Most inboxes truncate subject lines at 60 characters — mobile cuts even earlier at 30–40. Write for the mobile preview.
0CharactersLimit: 60
60Remaining
0Words
0Lines
0Hashtags
0@mentions
0URLs
Tips for this platform
30–40 chars on mobile
Most mobile inboxes cut subject lines at 30–40 characters. Majority of email opens happen on mobile.
40–50 chars optimal
Studies show 40–50 chars gets the highest open rate. Shorter doesn't hurt; longer does.
Avoid spam triggers
All caps, excess exclamation points, "FREE", "URGENT" — all hit spam filters.
Front-load the hook
The first 3–5 words matter most — that's what readers scan.
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Email Subject Line Counter
Email subject lines have no technical limit, but every inbox truncates somewhere — and most people open email on their phone. Writing for the mobile preview is non-negotiable.
Subject line length by inbox
- Gmail (desktop): ~70 characters visible
- Gmail (mobile): ~30–40 characters
- Outlook (desktop): ~60 characters
- Apple Mail (iOS): ~35 characters
- Yahoo: ~43 characters
What to include
- Benefit or hook in the first 5 words
- Personalization lifts open rate 26% (Campaign Monitor)
- Numbers draw the eye — "7 ways", "50% off"
- Preheader text is a second chance — many clients show 40–100 extra characters